Microelectromechanical systems (MEMS) include micromechanical elements, actuators, and electronics. Micromechanical elements may be created using deposition, etching, and/or other micromachining processes that etch away parts of substrates and/or deposited material layers or that add layers to form electrical and electromechanical devices. One type of MEMS device is called an interferometric modulator. As used herein, the term interferometric modulator or interferometric light modulator refers to a device that selectively absorbs and/or reflects light using the principles of optical interference. In certain embodiments, an interferometric modulator may comprise a pair of conductive plates, one or both of which may be transparent and/or reflective in whole or part and capable of relative motion upon application of an appropriate electrical signal. In a particular embodiment, one plate may comprise a stationary layer deposited on a substrate and the other plate may comprise a metallic membrane separated from the stationary layer by a transparent medium (e.g., an air gap). As described herein in more detail, the position of one plate in relation to the other plate can change the optical interference of light incident on the interferometric modulator. Such devices have a wide range of applications, and it would be beneficial in the art to utilize and/or modify the characteristics of these types of devices so that their features can be exploited in improving existing products and creating new products that have not yet been developed.
Conventional interferometric modulator display devices typically include a recessed backplate. The recessed backplate generally serves two purposes. First, the recessed backplate protects the interferometric modulator—e.g., the pair of conductive plates. Second, the recessed area within the backplate provides space for desiccant to be deposited. The desiccant absorbs moisture within an interferometric modulator display device. As interferometric modulator display devices increase in size, the recessed backplate more easily deflects under external pressure (e.g., when the interferometric display device is handled by a user). Due to the deflection, the recessed backplate can touch the interferometric modulator which can lead to breakdown of the interferometric modulator display device.
Accordingly, what is needed is an improved design for an interferometric display device to reduce backplate deflection caused by external pressure applied to the interferometric display device. The present invention addresses such a need.